950
FXUS66 KMTR 061741
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
941 AM PST Sat Dec 6 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 250 AM PST Sat Dec 6 2025

 - Persistent forecast through the next seven days with benign
   conditions and no precipitation expected

 - Impacts from Tule Fog in the North Bay and interior East Bay
   valleys

 - Next chance for rain towards the middle of the month

&&

.UPDATE...
Issued at 845 AM PST Sat Dec 6 2025

Satellite imagery shows the stratus deck extensively covering the
Bay Area valleys, extending a little bit into the corridor between
northern Monterey County and the San Juan Bautista area, while
most of the Monterey Bay region and the interior Central Coast
remain clear. The loop shows a couple of interesting eddy patterns
over the San Francisco Bay which will make come of the short-term
stratus development a little harder to predict, but the overall
trend should be a slow and gradual mixing out through the morning
and afternoon hours. The main forecast question will be how fast
the stratus mixes out over the North and East Bay valleys, as the
cooler temperatures across both regions are dependent on the
stratus lingering over the region.

DialH

&&

.SHORT TERM...
Issued at 250 AM PST Sat Dec 6 2025
(Today and tonight)

Satellite imagery overnight reveals a different scenario than the
last few nights. Tule Fog remains persistent across the Central
Valley, West Delta, and far East Bay Valleys. The change is a
redevelopment of the marine layer as high pressure builds
overhead. There is stratus along portions of the coastal waters
and Bay Area with the Central Coast remaining cloud free. There
was a Cold Weather Advisory in effect for portions of the North
Bay, but an influx of low level moisture/stratus limited
widespread temps below 36 degrees. In fact, a few places saw an
increase in temperatures once the stratus developed. Therefore,
cancelled the advisory. Another interesting note are the temp
spreads across the N Bay from valley to mts with upper 30s coldest
in the valleys and low 50s highest peaks. The warmer temps are
likely being enhanced by NE winds above the stratus deck. One
weather impact that hasn`t changed is patchy dense fog impacting
the N Bay and E Bay Valleys. It`s patchy and not widespread enough
to warrant a dense fog advisory as of this writing.

Rest of today and tonight: clouds across the Bay Area will be slow
to clear through late morning. A cool and damp start to the day in
those locations. Outside of the stratus, temperatures are colder,
but not as cold as yesterday. Slightly warmer temps likely due to
some weak offshore flow as well. For this afternoon expect a few
clouds passing overhead as a weak front to the north washes out
against the ridge of high pressure. Given lingering stratus and
Tule fog went on colder side of guidance for Max Temps in the N
and E Bay with Upper 50s to 60s. Elsewhere, generally 60s to a
few near 70. For tonight the ridge overhead strengthens a little.
This will help to compress the marine layer. In the big picture,
not a lot of change expected in overall sensible weather with
clouds and fog impacting N and E Bay and some of the Bay Area.

&&

.LONG TERM...
Issued at 330 AM PST Sat Dec 6 2025
(Sunday through Friday)

Solid agreement with model guidance through at least Friday as
high pressure dominates CA. A gradual warming trend is expected
with peak warmth Wed-Fri as temperatures soar above normal with
interior highs reaching the upper 60s to mid 70s. The challenge
next week will be N and E Bay temps and potential Tule fog impacts
keeping temperatures colder. There continues to be a few weak
systems passing well to the north, which may lead to some drizzle
over the coastal waters but land areas remain dry.

Friday and beyond - We`ll continue to monitor a lowered end chance
for a pattern change. Cluster analysis has a few clusters
breaking down the ridge. However, operational ensemble guidance
keep the ridge locked in or flattens it with zonal flow. We`ll see
how this changes over the coming days.

&&

.AVIATION...
(18Z TAFS)
Issued at 940 AM PST Sat Dec 6 2025

LIFR to IFR conditions across much of the Bay Area this morning,
while VFR conditions prevail at the Monterey Bay terminals. Low
ceilings and/or visibilities are forecast to improve by around 20Z
and give way to mostly VFR conditions. Onshore winds increase by
mid- to-late afternoon across the San Francisco Bay and Monterey
Bay terminals. High confidence for low ceilings and/or
visibilities for the North Bay and East Bay with moderate
confidence for the Bay Area terminals late tonight through Sunday
morning. Moderate to high confidence for VFR conditions to prevail
through much of that TAF period for the Monterey Bay terminals.
Low clouds and/or fog look to improve by midday Sunday.

Vicinity of SFO...IFR conditions across much of the region this
morning. Conditions are forecast to improve by 19Z-20Z and give
way to VFR throughout the remainder of the afternoon. Moderate
confidence for IFR conditions to return either late tonight or
early Sunday morning as wind speeds turn more offshore. Onshore
winds are forecast by Sunday afternoon with VFR conditions.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR through the TAF period. Light to
southerly winds prevail this morning and are forecast to become
onshore by early-to-mid afternoon. Winds diminish overnight and
become southerly early Sunday morning.

&&

.MARINE...
(Today through Thursday)
Issued at 845 AM PST Sat Dec 6 2025

Fresh northwesterly winds persist through this weekend and into
the middle of next week. Strong to near gale force gusts will be
possible through this weekend. Moderate seas with wave heights 6
to 8 feet across the outer waters this weekend. A new, long period
northwesterly swell is anticipated by Wednesday of next week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory until 3 PM PST Sunday for CAZ006-506-508-
     529-530.

PZ...Small Craft Advisory until 3 AM PST Sunday for Pt Pinos to Pt
     Piedras Blancas 0-10 nm.

     Small Craft Advisory until 9 AM PST Sunday for Pigeon Pt to Pt
     Pinos 10-60 NM.

&&

$$

SHORT TERM...MM
LONG TERM....MM
AVIATION...RGass
MARINE...RGass

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